Hydraulic torque converter



Sept. 18, 1945. R. LANG ETAL 2,384,841

HYDRAULIC TORQUE CONVERTER Filed June 18, 1941 5 Sheets-Sheet l Jrsbn yon Fuhldnd. Hcrmann Gras Sept. 18, 1945. R. LANG ET AL 2,384,841

HYDRAULIC TORQUE CONVERTER Filed June 18, 1941 5 Sheets-Sheet 2 /nvemor Rmhard Lang Jrgen wn Fahldnd Hermann Gros sepf. 18,l 1945. 'R LANG ET AL 2,384,841

. HYDRAULIC TORQUE CONVERTER Filed June 18, 1941 5 sheets-sheet 5 /nveno/w.- Rlchard. Lan Jrgen van F Land. Hermann Grof` Sept. 18, 1945. R. LANG ET AL 2,384,341

HYDRAULIC TORQUE CONVERTER Filed June 18 1941 5 Sheets-Sheet 4 Avvento/$.- Rlchard. Lan drgen von Fah Land Hermann Gr'o` u 354. QW 1@ 7 Sept. 18, 1945.

R. LANG ET AL HYDRAULIC TORQUE' CONVERTER Filed June 18 1941 5 Sheets-Sheet 5 Fly. 7

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Patented Sept. 18, 1945 HYDRAULIC TORQUE CONVERTER Richard Lang, Ravensburg, and Jrgen von Fah-l land and Hermann Gros, Friedrichshafen, Bodensee, Germany; vested in the Alien Property Custodian Application June 18, 1941, Serial No. 398,686 In Germany June 18, 1940 3 Claims.

Our invention relates to hydraulic torque converters and hasspecialreference to converters of this kind as they are used in connection with internal combustion engines because of their favourable adaptability to the turning moment o ver a certain portion of the transmissions. They are also `made use of in connection with mechanical change speed gears when it is necessary for the transmission to cover a large area of secondary numbers of revolutions, as for example in the driving mechanism of rail cars.

A main disadvantage with hydraulic torque converters in such mechanisms is the circumstance that the disengagement and re-engagement of the transmission can only be perfected slowly or by means of additional devices and with shocks. all expediting steps (increase of the emptying cross section and of the filling pumps) lasts at least several seconds and as an interruption in transmission for such a long period is not admissible, it became necessary to provide special friction clutches in addition to the hydraulic power transmission permitting these to remain lled while the friction clutches are disengaged. The dimension and the weight of such clutches are extraordinary in connection with high performances, their mounting is dinicult and they require large operating devices.

The greatest disadvantage of such friction clutches connected to hydraulic transmissions is that the centrifugal forces of therotating parts of the friction clutch and of the hydraulic transmission make theengagement of the clutch dii.'-y ficult. They cause great shocks when starting (engagement of the clutch) and when changing speed, such shocks being not only disagreeable in vehicles but causing great wear, especially if the vehicle with great performance has to be driven at low speed, for example when towing or shifting other cars. `If, for instance, a rail car which has a transmission witha friction clutch situated behind a hydraulic torque converter starts a heavy shock will occur ,when the clutch half in connection with the rotating secondary part of the converter engages the driving device for the wheels which are still at rest. Similar difficulties will occur in connection with'transmissions having a plurality of hydraulic torque converters or having a vgear transmission in ad- As the emptying and filling in spite of circuit thus causing its separation from the working transmission.

By our invention we do not intend to increase @the eciency of the transmission; the turbine wheel is only shifted for the purpose of separating the secondary part out of the circuit of the hydraulic converter. As this state of separation is only short in time it does not matter that during this period the incoming primary' performance, even if it be the maximum output of the motor, is transferred into whirls, shocks and friction inside of the transmission, as it is not a normal state but occurs only when the transmission is interrupted.

. According to our invention, we further improve the prevailing conditions by providing means for braking the turbine wheel or reducing its speed of rotation after it has been shifted out of the hydraulic circulation, Thus the speed of rotation of a clutch half which may be situated behind the hydraulic 'converter and connected to a mechanical change speed gear is also reducedl so that within a short time that speed of rotation is reached which allows for final clutch engagement. Consequently,` the time period necessary for a speed change is considerably reduced. Besides, it is not necessary to provide additional devices for quick speed reduction of the driven parts behind the torque converter, while would require additional space.

It is preferred, according to our invention, to shift the turbine wheel so far towards the wall of the casing that there is only a small intermediate space so that the friction and whirling of the liquid in rotation with the wheel causes its braking; or blades may be provided on the casing wall causing speed reduction of the circulating fluid and consequently also of the wheel the narrow space at the circumference of the turbine wheel is again fed to this wheel, thus causing a pumping effect which results in. braking of the wheel. For the purpose of increasing this eect there may be provided channels or gaps in the wall of the housing where it surrounds the turbine Wheel when withdrawn, for leading the liquid over to the other side of the wheel disc.

Another advantageous construction, according to our invention, is the provision of friction surfaces, on one side of the .turbine wheel and on the corresponding inner side of the housing wall.4

The current in the hydraulic converter itself continues in the same manner after the turbine wheel is shifted out, the output being received by the hydraulic circuit as before. lAfter shifting in the turbine wheel again,- the output is immediately transmitted again by the hydraulic converter. When putting in the turbine wheel there can be no shocks whatsoever owing .to differences in the speed of rotation, these being entirely suppressed by the hydraulic effects of' the circuit.

' The invention may be applied to power transmissions oi the purely hydraulic kind as well as to transmissions with hydraulic circuits and change speed gears or .to such transmissions in which hydraulic circuits are bridged over by direct coupling.

According to our invention, the blade-rim of the turbine wheel is connected with a driven shaft by a suitable support through the ports of which the pressure in the spaces before and behind this part is equalized so that there are not opposed in these spaces any essential counter-pressures to the shifting oi' the turbine Wheel.

It is useful to connect the turbine wheel with aO pressure-operated cylinder or piston by means of which the turbine wheel may be shifted out of the hydraulic circuit or pushed into it, this latter being its position in the normal operation.

According to our invention, there is arranged, furthermore, on the shaft of the turbine wheel a disc or similar part which seals the shifting space, that is the Space into which the .turbine wheel is shifted, from thecircuit spaces of high pressure. By this 'arrangement it is provided that particularly the highest pump pressure cannot counter-act the shifting operation of the turbine wheel. 'it is advantageous for the turbine wheel to be arranged and designed in such a way as to be forced, preferably by pressuremeans, against side-faces of the above-mentioned disc.

When shifting the turbine wheel by pressuremeans the operating member connected with the tunbine wheel will be designed (in the further'development of the invention) as a stepped piston, the surface acting in the direction of en gaging being considerably larger than the surface acting in the direction of disengaging, the former having, for instance, double the size of the latter. if there is, therefore, no pressure supplied to the space acting in the direction of disengagement the turbine wheel is kept en- Y gaged by itself at any speed of rotation, because `the centrifugal force which exists in the liquid contained in the space of engaging, creates constantly a pressure in the direction of engaging the turbine wheel.

In a further development of .the invention, the turbine wheel is connected at its smallest rim diameter with a ring by which the pump wheel is locked up outwards in the disengaged assess;

position of the turbine wheel. This arrange ment offers advantages in certain cases because it. provides that there are fewer whirls in the hydraulic circuit when the turbine wheel is disengaged.

I-Iaving given a general description of our invention we now want to point it out more in detail having reference to the drawings which represent several examples embodying our invention.

In the drawings:

Fig. i is a diagrammatic, longitudinal section of a hydraulic torque converter embodying the invention, the turbine wheel being shown in the hydraulic circuit in full lines, and out of the circuit in broken lines.

Fig. 2 and Fig. 2-a are views 1.11 Fie. i.. showing another form of the device, Fig. 2 showing the wheel out of the circuit, and Fig. Z-a showing the wheel in the circuit.

Fig. 3 and Fig. 3`a`are View siiniiar to Figs. 2 and 2-a, respectively, showing another form of the device. y

Fig. 4 and Fig. i-a, are views similar to Figs. 2 and Z-a, respectively, showing another forni oi the device.

Fig. 5 is a view similar to Fig. 3, showing other form of the device.

Fig. 6 is a view similar'to Fig. 2-c, showi another form of the device.

Fig. 'i' is a partial section ci another .icm of the device.

In Fig. l i is .the primary shaft, and the secondary shaft of a hydraulic torque converter. 3 is a relier bearing carrying both the shafts. is a pump wheel, 5 the turbine wheel, G the guide apparatus of the converter with the guide blades il. @is a pipe bend, adjacent to the cas ing part t, in the hub i@ ci which is carried the hub ii of the turbine wheel 5. necting the rim of the blades i5 of the turbine A Wheel 5 with the hub ii. This disc is provided with apertures i7. i3 are splines on the 2 along which by means of heyways i@ arranged in the hub di, the turbine wheel d can be shifted. 2@ is a collar of the shaft E against which generally the hub ii bears. i@ is the space between the pump wheel i and. the disc i2; it is the space between the latter and the wail the casing d. iii is a spare space the guide apparatus. 2i is a circuiar in hub i i operated in the conventionai manner by a hand lever 22 by means of orir By means of the hand lever the turbine wheel 5 may be shifted from the position ci normai operation as shown in i, into the dotted line position, the turbine wheel remaining ccnnecteci by means of the ireys i3 and it with the shaft 2.

During the displacement the liquid contained in the space it is allowed to enter the space ifi through the apertures il'. After the turbine wheel 5 has been shifted to the broken line position the hydraulic circuit no longer transmits the torque to the turbine wheel, whereas the circuit itself is not interrupted as its liquid continues to circulate by means oi the pump wheel il via the guide apparatus i. If the position of the fuel supply (not represented) has not been changed, the pump wheel will continue to transform, according to its characteristic, its power input into delivery and pressure. Therefore, the same energy has to be put in as before; but the number of revolutions of the pump wheel may change somewhat. The energy is absorbed by i2 is a'disc ronturbulence, percussion and friction (production of heat). The extension of the circuit by means of the space I6 is harmless in general; if necessary, this space can be designed as required.

Before putting into operationv such a power transmission, for instance, before starting a car. the power transmission of which is provided with a hydraulic circuit according to Fig. 1, the shaft l and consequently thepump wheel 4 is started while the turbine wheel is shifted out (dotted line position) and the fuel supply of the driving engine will be regulated according to the energy required for the start of the vehicle. The pump wheel 4 maintains the circuit according to the energy input. At first, the turbine wheel 5 is out of operation and at rest and ljust before the car is to start the turbine wheel is shifted into the position shown in Fig. 1 in full lines. Thus the torque is transmitted to the turbine wheel according to the size of the hydraulic torque converter, and the car starts smoothly, the number of revolutions of the shaft 2 and, consequently, the car speed increasing according to resistance.

If the hydraulic torque converter, shown in Fig. l, is connected to a change speed gear, the turbine 5 can be disengaged" from the circuit in the same way beforechanging over from one speed to another, whereupon the gear change can be eifected in the conventional manner. After the gear change the turbine wheel 5 is re-engaged by shifting it back into the circuit. During the changing-over operation the driving energy needs no reduction. However, it is also possible to reduce it in the usual .way during the changing-over period.

In Figs. 2 and 2-a, 3i is the primary shaft, 32 the secondary shaft of a hydraulic torque converter comprising the pump wheel 34,' the turbine wheel 35 and the guide apparatus 36 with the guide blades 31 and the bend pipe 38. 39 is a casing adjacent to the bending pipe 38. The turbine wheel 35 can be displaced within the cas-- ing. The turbine wheel is connected by means through the circular space 62 Ibetween .the tube Y 6| and the portion of shaft 60 and via. the bores 64 to the space on the left hand of the piston 5|,

the turbine wheel 35 can be shifted back from of a disc 42 to a pressure-operated cylinder 43 made up of the cylinder bottom 44, the side walls and the cover 46 and connected at the other hand Iby means of keyways 41 to keys 48 which are arranged on the driver 49 located immovably and incapable of being turned on the shaft 32. The driver, in its turn, is surrounded by the casing hub 50 adjoining casing 39.

In the bore of the shaft 3| is arranged a piece of shaft 32, in lthe centre of which is situated a tube 6|. the tube 6| and the portion of shaft 60 as well as the space 63 within the tube 6| permit the pressure supply to the cylinder 43. There are bores 64 and 65 in the portion of shaft v60 connected to the spaces 62 and 63, respectively, and lead to the centre of the cylinder 43, the bores 64 on the left hand and the bores 65 on the right hand of the disc piston 5| connected to the portion of shaft 60. AFitted on the shaft 60 The circular space 62 between is an intermediate ydisc-shaped piece 66 at the outer rim of which is provided a sealing surface 69.` A similar' sealing surface '10 is arranged cn the disc 42 of the turbine wheel 35.

The turbine wheel 35 is shifted bypressure means, for instance, pressure oil, via the spaces its disengaged position into the circuit so that power is transmitted again to the turbine wheel in the conventional manner.

During the engaged position of the turbine wheel both the surfaces 63 and 10 are in touch and are kept in this position by means of the pressure oil fed to the space on the left hand of the solid piston 5|. The interval between the lpump wheel 34 and the turbine wheel 35 where exists a high pressure has no outside connection.

Consequently; no high pressure can enter the" space between the discs 42 and 66. l

The result of the displacement of the turbine wheel 35 is the same as that in our example given in Fig. 1. Y

The joints conveniently provided inthis arrangement are indicated in Figs. 2 and 2- -a between the different parts the object of which can easily be seen from the illustration.

The example of Figs. 3 and 3--a is similar to that of Figs. 2 and 2-'a. Here, too, there is provided an intermediate piece 66' fitted with a sealing surface separating the spaces of high pressure. The blade rim 80 of the turbine wheel 3| is provided with an angle ring 82, 83 situated during normal operation in the space 85 of the middle'part 84 of thetorque converter. When the turbine wheel is shifted outwards the pump wheel 34' is blocked at the outer periphery by the angle leg surface 82 running in the direc tion of the periphery of the angle rim. Thus the supply of the circuit is interrupted.

In the example shown in Figs. 4 and 4`a., the

turbine wheel |05 joins a ring |06 which is connected by means of the disc ||2 to a stepped piston III. The latter can be shifted in the cylinder |03 which is connected to the secondaryshaft |02 in a way that it cannot be turned or shifted. |0| is the primary shaft, |04 the pump wheel. Hub part ||4 of the stepped piston III can be shifted in the hub bore |26 arranged at the intermediatev piece H6. Rotor |05 is equipped at its external periphery with keys |23 whichcan be shifted in the corresponding keyways |24 of the guide part |03. ing surfaces of' the stepped piston I||; |21 and |28 are the pressure means spaces of the cylinder 03. In the bore of the shaft |0| is situated a portion of shaft |60 forming an extension of shaft |02 to the left and carried in a roller bearing of shaft |0|. In the bore of the portion of shaft |60 is situated the tube ||6| the extension of which on' the right hand forms a bore |66 in the shaft |02 fromwhich radiate radial bores |65. The space |62 between the portion of shaft |60 and the tube |6| corresponds to the space 62 in Fig. 2, and the bore |63 of the tube I6| corresponds to the bore 63 of Fig. 2. From the circular space |62 radiate lloes |64,- leading into the middle of the cylinder In the example of Fig. 4, there is constantly a supply of oil through the bores |63, |66 and |65 without or with a slight overpressure into the space |121. The displacement of the turbine wheel |05 outwards is performed by means of supplying pressure oil through the space |62 and the bores |64 into the space |28 in front of the surface |26 |25 and |26 indicate the operat- Y of the step piston i i i. When the oil supply under `pressure is interrupted the turbine Wheel is engaged by the fact that the surface 82d of the step lpiston i ii in the space i2? is constantly pressureoperated'due to the centrifugal force of the liquid in this space. The dimensions of surface idd ci the step piston i ii ensure that turbine wheel idd is kept in its engaged position in the circuit at every speed oi rotation.

Figs. 5 and 6 show tdi the primary shaft, 26M the secondary shaft of the converter. 283 is a roller bearing carrying both shafts. 261i is a pump Wheel, 205 the turbine wheel, 2d@ the guide apparatus of the converter. 2d@ is a bend pipe joining the guide apparatus and adjacent to the casing part 2d@ inv the hub 2i@ of which is carried a driver 2i i arranged on the shaft dit?. in a way that it cannot be turned or shifted. i. i 8 is the disc connecting the rim oi the turbine Wheel ddd with the `4hub 2id. The driver dei and the cylinder 22d v connected to the disc i@ are coupled by means of dogs or teeth 2id, 2id ior rotation, however, in a Way that the turbine 'wheel can be shifted in the directiono the sexis. The disc 2id is provided -With apertures 2i 2id is the interval between the casing ivali 2d@ and the disc 'Ln the bore of the shaft is located extension ddd of the shaft inthe centre of which is situated a tube The circular space i222 between the tube 2M an the portion oi shaft 22@ as Weil as the space Las within the tube 522i ensure the supply of pressure fiuid to the cylinder 2253. in the 'shaft portion there are arranged the bores and 22@ which are connected toL the spaces and and lead into the centre of the cylinder 22d-the bores on the ieft hand, the bores to the right hand oi the solid piston which is connected to the shaft l portion Fixed to the shaft 22:@ is a discshaped intermediate piece Edif at the external rirn of which is providedla joint surface 22d. An identical joint surface 2d@ is arranged on the outside of the disc 2id of the turbine wheel 2%.

The displacement oi the turbine wheel. Eil@ is eiiected by supplying pressure iiuid, for instance oil pressure, via the spaces 222 and '223 to the cylinder 226i. When the turbine Wheel 265 is in the engaged position as shown in Fig. d, the cylinder 22d and consequently the turbinewheel ddd can be shifted to the right by supplying pressure oil through the space 22d and the bores 22d to ther space on the right hand of the piston @Si so that the turbine wheelyd is shifted into the position as shown in Fig. 5 in which it is withdrawn from the hydraulic circuit of the converter. The circuit itself continues to be maintained. By supplying pressure oil through the circular space 222 and the bores 225 into the space on the left hand of the piston 23E, the turbine wheel 265 can be shifted back into the circuit from the disengaged position. 233 is the interval at the external periphery of the turbine Wheel 295, 23d the inlet cross section of this wheel, 235i are ducts or gaps.

\ 'When disengaged from the circuit, the turbine wheel 265 approaches the Wall 2tlg so close that there is only the interval 2id between the disc 2G53 and the wall' 289. By means of the liquid existing in the interval 2id the number of revolutions oi the turbine wheel is quickly reduced due to friction and turbulence. The same process takes place when, as shown in Fig. 6, the blades 2id are provided preventing the liquid in the interval 2l@ from circulating with the disc 2id thus exercising also a braking action on the disc 2 i3.

l clutch haii* in the change accessi The blades 2id may extend in the radial and the peripheral direction over 'so large a surface and into the wall 2Q@ as isnecessary to attain the dcsired braking eect.

By means o the apertures 2li provided in disc Sii@ the liquid escaping at the externa?. riphery oi' the turbine wheei den? via the int i 23d to the right iiows again via the interval fi i3 back to the left and thus in iront of, the inlet cross section 25C of the turbine Wheel. '5y the arrangement of the apertures 2 ii a constant circulation of the liquid is ensured by means of turbine Wheei 2de.

pumpingeicct may he considerably iffcreased ii in the Wall oi the casing 2d@ ducts c: gaps 235 are provided by means of which, turbine wheel 205 being disengaged, the arnoL ci entering liquid between the blade spa I the turbine `zvheel ZEBE the interi/ai i2 i crused.

The construction, accor particuiariy important arranged behind the hymn" i in order to brake the tu engaging speed. But e in cese of. purely hydraulic out a combination with speed gear).

in the construction siih 2id' and the casing wel braking surfaces 2M ani disengaged the turbine c rated` position so that the bi and 262 are pressed ciose to ing a braking oi the turbine f rotating parts connected tively.

0111* invention eliminates not only the and tedious emptying or the operating liquid ci the hydraulic torque converter but combines, thermore, as shown by the examples, ail the advantages of such a converter with those of a friction clutch without the didculties arising in such a combination normally under service conditions.,

With hydraulic torque converters, according to our invention, when used in combination with change speed toothed gearings as usually applied to motor cars, the shiftable turbine Wheel design permits eliminating a special friction clutch otherwise necessary for the operation of the change speed toothed gearing.

We do not Want to be limited to the details described or 4represented in the drawings, as many variations will occur to those skilled in the art ree?. and.

YWitliout deviating from the scope oi our invention having one portion disposed in said driving shaft;

and another portion projecting therefrom and journaled in said wheel, and another portion pro- .iecting therefrom; a turbine Wheel slidable on said last mentioned projecting portion of the driven shaft, and shiftable into and out of the hydraulic circuit; uid pressure operating means for shifting said turbine wheel, disposed on said last mentioned projecting portion of the driven shaft; and channels for feeding uid under pressure to said operating means, said channels passing through the portion of the driven. shaft dis'- posed in the driving shaft and the portion journaled in the pump wheel, and into the portion of l0 the driven shaft projecting from the pump wheel.

3. In a hydraulic torque converter, the combination of a pump wheel; a turbine wheel shift- 

